docs: def mother(year=None):
      """
      the 2nd Sunday in May
      :param year: int
      :return: Mother's day
      """
      may_first = datetime.date(_year, 5, 1) if not year else datetime.date(int(year), 5, 1)
      weekday_seq = may_first.weekday()
      return datetime.date(may_first.year, 5, (14 - weekday_seq))